4-6-0 Steam Locomotives in New Zealand

Class U (Locobase 5184)

Data from John Garner and his comprehensive website [] (October 2002; last accessed 10 June 2025). See also "NZR U class" in Wikipedia at [], last accessed 10 June 2025. Addington shops' works numbers were 10-11, 16-17, 20-23, and 58 in 1894-1895, 1897-1899, and 1903.

Garner described the various "firsts" these Ten-wheelers represented: "It was this class that introduced the stylish two-window cab and the 4'6" driving wheels that were subsequently regarded as standard for express engines. They were the first express locomotives to use Walscherts valve motion, and were the first to use the 4-6-0 wheel arrangement, although originally designed to use 4-4-0." Wikipedia credited locomotive superintendent T F Rotherham for setting the requirements.

But, he added, the Fs were less successful battling the Northwest Wind on the Canterbury Plain than had been hoped "although satisfactory in calm weather." Wikipedia's mixed verdict praised the design for handling curves well and riding easily, but quioted driver Jack Ewart: blunt negative "... she [the U class] failed when the Canterbury Nor'wester was blowing and would not stand thrashing and consequently lost time."

They were eventually moved to Southland for branch-line operations and switching duties. Yet they persisted thanks to a 1920s program to add superheaters and piston valves. Further upgrades in 1935-1940 fitted tender cabs and the Waikato spark-arresting stack.

After retirements, several of the class joined other discarded locomotives in Southland rivers to assist in erosion protection.

Class Ua (Locobase 5185)

Data from John Garner and his comprehensive website [] (October 2002; last accessed 10 June 2025.). See also "NZR Ua class" in Wikipedia at [], last accessed 10 June 2025. Works numbers were 4502-4507 in 1899.

In size these were repeats of the locally built Us of five years earlier, but with lower drivers. Garner reported " they did not steam well and their tender axleboxes tended to run hot." But a paid-for locomotive offered its own charm and they handled expresses out of Dunedin for years. Wikipedia explained that they accumulated more revenue miles at lower cost than other 4-6-0 classes of the time.

The railway later resorted to a common change by extending the smokebox, which seems to have improved steaming. Two or three later were refitted with superheated boilers.

Retirements began with three leaving in 1934 and one each in 1935-1937.

Class Ub (Locobase 2706)

Data from John Garner and his website [] (October 2002). Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 21, p. 221 and Volume 23, p. 124; and Baldwin's Record of Recent Locomotives, Volume 24, pp 20-21. Works numbers were 16049 in November 1898; 16042-16048, 16050-16051 in December; 18574-18583 in June 1901.

These US-built locomotives handled the Christchurch-Dunedin expresses quite capably, even if some critics disliked the firebox separating the two crewmembers. (In the United States, such an arrangement was outlawed before too long.) Belpaire boilers and typical North American layout characterized all 20 engines, but the ten delivered in 1901 used Walschaerts valve gear to drive piston valves.

The first batch arrived in November and December 1898. They were numbered in order of their works numbers, the series running 278-287. The second batch -- 328-337 -- all arrived in June 1901.

All of the first batch were retired in the mid-1930s, 287 leading in June 1933 and the 280 going in September 1936. Three of the second batch -- 328, 333, and 334 -- were withdrawn in March 1935. The next to go was 335 in June 1953 with four more in March 1955 (331, 332, 336, 337) and the last two in January 1957.

Class Ub (Locobase 4084)

Data from "Brooks Ten-Wheel Passenger Locomotives for the New Zealand Government Railways", Railroad Gazette, Volume 33, No. 40 (4 October 1901), p. 678. Works number was 3925 in August 1901.

This was a larger engine than the Ucs delivered in the same year by Sharp, Stewart although they had the nearly the same power dimensions. It was an elegant locomotive with clean British lines and a well-shaped Belpaire firebox.

It was the only one of its type, according to John Garner and his website [] (October 2002, last accessed 9 February 2017) although Baldwin delivered 20 very similar, but slightly smaller, engines (see Locobase 2706). Garner reports that upon its arrival, the Brooks engine "was the largest and most powerful 'Ten-wheeler' in New Zealand."

Class Ub (Locobase 20150)

Data from "Ten-Wheeler for the New Zealand Government Railways", Railway & Locomotive Engineering, Volume 14, No. 11 (November 1901), p. 494. See also John Garner's , last accessed 9 February 2017 at "Class Ub 4-6-0" [] . Works number was 3275 in 1901.

The US-origin R&LE began its account of the single locomotive described with a bit of stars-and-stripes flag-waving: "With all the disparaging remarks made by our English friends against the American locomotive, we find that foreign countries still keep ordering them, and we also find that the tendency is to take the pure and simple American locomotive instead of the hybrid which it was the custom to specify a few years ago,"

R&LE went on to describe the British and British colonies' railways preference for copper fireboxes and either brass or copper tubes as "a fad" (...instead, Locobase suggests, of a reasonable choice based on decades of service). The steel Belpaire firebox in the new Ub variant joined with iron tubes in a test case for those materials.

Despite the boost from an American journal, the Richmond engine turned out to be a dud according to John Garner's website. It was, he reported, known as a "poor steamer." (Having called out the R&LE for its bias, Locobase now gives equal time to the skeptic who might argue that the crews responded more to the alien materials than to the engine's actual capability. For one thing, it was smaller than the Brooks engine (Locobase 4084) that was so well regarded.)

Its retirement in October 1933 was one of the first in the Ub class.

Class Uc (Locobase 2707)

Data from John Garner's [], last accessed 7 September 2008 and 24 June 2025. See also the Midland Railway Heritage Trust website at[] . Works numbers were 4745-4754 in 1901.

An interesting example of a British engine of this vintage using constant-lead radial valve gear on piston valves. These operated on the South Island and were the slightly larger follow-ons to the popular Class Us.

But Garner's comment reveals the mediocre quality of this design" "With less adhesive weight, the 'Uc' was apt to wheel-slip badly, and it was a "great coal-scoffer" and not easy to fire."

According to the MRHT, which has preserved two of the engines, attempts to remedy the problems in the late 1920s by fitting seven of the class with superheated boilers was a "mistake". "The smaller U type superheated boiler reduced the grate area and firebox heating surface which then along with the larger cylinders made them hard to steam, particularly on long runs."

The saturated-boiler engines were written off in 1934-1936. The seven reboilered engines remained in service until the mid-1950s "hauling the Hokitika Express to Greymouth to connect with the Greymouth to Christchurch Express and also hauling and banking fully loaded coal trains from Reefton up over the well know Reefton Saddle and through the tunnel and down to Tawhai."

But they were never well-liked by their crews.

It may be that 369 and 370 survived retirement as bank fill in the Grey River because they were submerged in the Omoto Locomotive Dump and thus protected from the elements. Both were rescued in 2005 for rerstoration. Uc 366 emerged from a similar location at the Oamaru Locomotive Dump, but its condition led to a decision to reunite what remained and place it on static display.